I-Delta1ext-myc enhanced engraftment of human CD45+ or CD3+ T cells in the thymus of NOD/SCID β2m–/– mice. We transplanted 4.7 × 103 CD34+CD38– cells or all the progeny of 4.7 × 103 CD34+CD38– cells cultured for 16, 23, or 29 days with 5GF, I-Delta1ext-myc, and CH-296 into NOD/SCID β2m–/– mice, and the thymus was harvested after 9 weeks. (a) Total numbers of human CD45+ and CD45+CD3+ cells in thymus were assessed. (b) The proportion of cells expressing CD45 in thymic cells (left panel), CD3 in thymic engrafted CD45+ cells (middle panel), and CD4 and/or CD8 in thymic engrafted CD3+ cells (right panel) are shown. Data are representative of three independent experiments.